Grass block



FIG. 1 is a top perspective view of a grass block of my new design;

FIG. 2 is a front side view of the grass block of my new design;

FIG. 3 is a left side view of the grass block of my new design;

FIG. 4 is a right side view of the grass block of my new design;

FIG. 5 is a back side view of the grass block of my new design;

FIG. 6 is a top view of the grass block of my new design; and,

FIG. 7 is a bottom view of the grass block of my new design. 

CLAIM The ornamental design for a grass block, as shown. 